What is WCF?
Windows Communication Foundation (WCF) is an SDK for developing and deploying services on Windows. WCF provides a runtime environment for services, enabling you to expose CLR types as services, and to consume other services as CLR types.
WCF is part of .NET 3.0 and requires .NET 2.0, so it can only run on systems that support it. WCF is Microsoft’s unified programming model for building service-oriented applications with managed code. It extends the .NET Framework to enable developers to build secure and reliable transacted Web services that integrate across platforms and interoperate with existing investments.
Windows Communication Foundation combines and extends the capabilities of existing Microsoft distributed systems technologies, including Enterprise Services, System.Messaging, Microsoft .NET Remoting, ASMX, and WSE to deliver a unified development experience across multiple axes, including distance (cross-process, cross-machine, cross-subnet, cross-intranet, cross-Internet), topologies (farms, fire-walled, content-routed, dynamic), hosts (ASP.NET, EXE, Windows Presentation Foundation, Windows Forms, NT Service, COM+), protocols (TCP, HTTP, cross-process, custom), and security models (SAML, Kerberos, X509, username/password, custom).
What is SOAP?
Short for Simple Object Access Protocol, a lightweight XML -based messaging protocol used to encode the information in Web Service request and response messages before sending them over a network. SOAP messages are independent of any operating system or protocol and may be transported using a variety of Internet protocols, including SMTP,MIME and HTTP.
What is service and client in perspective of data communication?
A service is a unit of functionality exposed to the world. The client of a service is merely the party consuming the service.
What is End point ?
Every service must have Address that defines where the service resides, Contract that defines what the service does and a Binding that defines how to communicate with the service. In WCF the relationship between Address, Contract and Binding is called Endpoint.
The Endpoint is the fusion of Address, Contract and Binding.
What is endpoint in WCF? or What is three major points in WCF?
Every service must have Address that defines where the service resides, Contract that defines what the service does and a Binding that defines how to communicate with the service.
In WCF the relationship between Address, Contract and Binding is called Endpoint. The Endpoint is the fusion of Address, Contract and Binding.
1. Address : Specifies the location of the service which will be like http://Myserver/MyService.Clients will use this location to communicate with our service.
2. Contract : Specifies the interface between client and the server.It’s a simple interface with some attribute.
3. Binding : Specifies how the two party will communicate in term of transport and encoding and protocols.
Why do we need WCF?
What is binding and how many types of bindings are there in WCF?
A binding defines how an endpoint communicates to the world. A binding defines the transport (such as HTTP or TCP) and the encoding being used (such as text or binary).
A binding can contain binding elements that specify details like the security mechanisms used to secure messages, or the message pattern used by an endpoint.
WCF supports nine types of bindings.
1. Basic binding :
Offered by the BasicHttpBinding class, this is designed to expose a WCF service as a legacy ASMX web service, so that old clients can work with new services. When used by the client, this binding enables new WCF clients to work with old ASMX services.
2. TCP binding :
Offered by the NetTcpBinding class, this uses TCP for cross-machine communication on the intranet. It supports a variety of features, including reliability, transactions, and security, and is optimized for WCF-to-WCF communication. As a result, it requires both the client and the service to use WCF.
3. Peer network binding :
Offered by the NetPeerTcpBinding class, this uses peer networking as a transport. The peer network-enabled client and services all subscribe to the same grid and broadcast messages to it.
4. IPC binding :
Offered by the NetNamedPipeBinding class, this uses named pipes as a transport for same-machine communication. It is the most secure binding since it cannot accept calls from outside the machine and it supports a variety of features similar to the TCP binding.
5. Web Service (WS) binding :
Offered by the WSHttpBinding class, this uses HTTP or HTTPS for transport, and is designed to offer a variety of features such as reliability, transactions, and security over the Internet.
6. Federated WS binding :
Offered by the WSFederationHttpBinding class, this is a specialization of the WS binding, offering support for federated security.
7. Duplex WS binding :
Offered by the WSDualHttpBinding class, this is similar to the WS binding except it also supports bidirectional communication from the service to the client.
8. MSMQ binding :
Offered by the NetMsmqBinding class, this uses MSMQ for transport and is designed to offer support for disconnected queued calls.
9. MSMQ integration binding :
Offered by the MsmqIntegrationBinding class, this converts WCF messages to and from MSMQ messages, and is designed to interoperate with legacy MSMQ clients.
What is contracts in WCF?
In WCF, all services expose contracts. The contract is a platform-neutral and standard way of describing what the service does.
WCF defines four types of contracts.
1. Service contracts : Describe which operations the client can perform on the service.
2. Data contracts : Define which data types are passed to and from the service. WCF defines implicit contracts for built-in types such as int and string, but we can easily define explicit opt-in data contracts for custom types.
3. Fault contracts : Define which errors are raised by the service, and how the service handles and propagates errors to its clients.
4. Message contracts : Allow the service to interact directly with messages. Message contracts can be typed or untyped, and are useful in interoperability cases and when there is an existing message format we have to comply with.
What is address in WCF and how many types of transport schemas are there in WCF?
Address is a way of letting client know that where a service is located. In WCF, every service is associated with a unique address. This contains the location of the service and transport schemas.
WCF supports following transport schemas
1. HTTP
2. TCP
3. Peer network
4. IPC (Inter-Process Communication over named pipes)
5. MSMQ
The sample address for above transport schema may look like
http://localhost:81
http://localhost:81/MyService
net.tcp://localhost:82/MyService
net.pipe://localhost/MyPipeService
net.msmq://localhost/private/MyMsMqService
net.msmq://localhost/MyMsMqService
What is the difference WCF and Web services?
1. Web services can only be invoked by HTTP. While Service or a WCF component can be invoked by any protocol and any transport type.
2. Second web services are not flexible. But Services are flexible. If you make a new version of the service then you need to just expose a new end point. So services are agile and which is a very practical approach looking at the current business trends.
How can we host a service on two different protocols on a single server?
Let’s first understand what this question actually means. Let’s say we have made a service and we want to host this service using HTTP as well as TCP.
You must be wondering why to ever host services on two different types of protocol. When we host a service it’s consumed by multiple types of client and it’s very much possible that they have there own protocol of communication. A good service has the capability to downgrade or upgrade its protocol according the client who is consuming him.
Let’s do a small sample in which we will host the ServiceGetCost on TCP and HTTP protocol.
Once we are done the server side coding its time to see make a client by which we can switch between the protocols and see the results. Below is the code snippet of the client side for multi-protocol hosting
Follows the ‘software as a service’ model, where all units of functionality are defined as services.
A WCF Service is a program that exposes a collection of Endpoints. Each Endpoint is a portal (connection) for communication with either clients (applications) or other services.
Enables greater design flexibility and extensibility of distributed systems architectures.
A WCF application is represented as a collection of services with multiple entry points for communications.
What are the main components of WCF?
1.Service: The working logic or offering, implemented using any .Net Language©.
2.Host: The environment where the service is parked. E.g. exe, process, windows service
3.Endpoints: The way a service is exposed to outside world.
Explain transactions in WCF.
Transactions in WCF allow several components to concurrently participate in an operation. Transactions are a group of operations that are atomic, consistent, isolated and durable. WCF has features that allow distributed transactions. Application config file can be used for setting transaction timeouts.
What are different isolation levels provided in WCF?
The different isolation levels:
1. READ UNCOMMITTED: – An uncommitted transaction can be read. This transaction can be rolled back later.
2. READ COMMITTED :- Will not read data of a transaction that has not been committed yet
3. REPEATABLE READ: – Locks placed on all data and another transaction cannot read.
4. SERIALIZABLE:- Does not allow other transactions to insert or update data until the transaction is complete.
How do I serialize entities using WCF?
LINQ to SQL supports serialization as XML via WCF by generating WCF serialization attributes and special serialization specific logic during code-generation. You can turn on this feature in the designer by setting serialization mode to ‘Unidirectional’. Note this is not a general solution for serialization as unidirectional mode may be insufficient for many use cases.
Windows Communication Foundation (WCF) is an SDK for developing and deploying services on Windows. WCF provides a runtime environment for services, enabling you to expose CLR types as services, and to consume other services as CLR types.
WCF is part of .NET 3.0 and requires .NET 2.0, so it can only run on systems that support it. WCF is Microsoft’s unified programming model for building service-oriented applications with managed code. It extends the .NET Framework to enable developers to build secure and reliable transacted Web services that integrate across platforms and interoperate with existing investments.
Windows Communication Foundation combines and extends the capabilities of existing Microsoft distributed systems technologies, including Enterprise Services, System.Messaging, Microsoft .NET Remoting, ASMX, and WSE to deliver a unified development experience across multiple axes, including distance (cross-process, cross-machine, cross-subnet, cross-intranet, cross-Internet), topologies (farms, fire-walled, content-routed, dynamic), hosts (ASP.NET, EXE, Windows Presentation Foundation, Windows Forms, NT Service, COM+), protocols (TCP, HTTP, cross-process, custom), and security models (SAML, Kerberos, X509, username/password, custom).
What is SOAP?
Short for Simple Object Access Protocol, a lightweight XML -based messaging protocol used to encode the information in Web Service request and response messages before sending them over a network. SOAP messages are independent of any operating system or protocol and may be transported using a variety of Internet protocols, including SMTP,MIME and HTTP.
What is service and client in perspective of data communication?
A service is a unit of functionality exposed to the world. The client of a service is merely the party consuming the service.
What is End point ?
Every service must have Address that defines where the service resides, Contract that defines what the service does and a Binding that defines how to communicate with the service. In WCF the relationship between Address, Contract and Binding is called Endpoint.
The Endpoint is the fusion of Address, Contract and Binding.
What is endpoint in WCF? or What is three major points in WCF?
Every service must have Address that defines where the service resides, Contract that defines what the service does and a Binding that defines how to communicate with the service.
In WCF the relationship between Address, Contract and Binding is called Endpoint. The Endpoint is the fusion of Address, Contract and Binding.
1. Address : Specifies the location of the service which will be like http://Myserver/MyService.Clients will use this location to communicate with our service.
2. Contract : Specifies the interface between client and the server.It’s a simple interface with some attribute.
3. Binding : Specifies how the two party will communicate in term of transport and encoding and protocols.
Why do we need WCF?
There is one main Bank system which is directly connected with the database, that provides other systems like ATM machine, Loan System data using various communication protocols like Remoting, web service, etc. For communicating with different Systems using different communication protocols, you have to know the API of that technology. In WCF, you have to just make different End points for different services. There is no need to learn a different API. You can use only one common API for communication with different System.
In WCF, you have to just make different End points for different services. There is no need to learn a different API. You can use only one common API for communication with a different System.
What is binding and how many types of bindings are there in WCF?
A binding defines how an endpoint communicates to the world. A binding defines the transport (such as HTTP or TCP) and the encoding being used (such as text or binary).
A binding can contain binding elements that specify details like the security mechanisms used to secure messages, or the message pattern used by an endpoint.
WCF supports nine types of bindings.
1. Basic binding :
Offered by the BasicHttpBinding class, this is designed to expose a WCF service as a legacy ASMX web service, so that old clients can work with new services. When used by the client, this binding enables new WCF clients to work with old ASMX services.
2. TCP binding :
Offered by the NetTcpBinding class, this uses TCP for cross-machine communication on the intranet. It supports a variety of features, including reliability, transactions, and security, and is optimized for WCF-to-WCF communication. As a result, it requires both the client and the service to use WCF.
3. Peer network binding :
Offered by the NetPeerTcpBinding class, this uses peer networking as a transport. The peer network-enabled client and services all subscribe to the same grid and broadcast messages to it.
4. IPC binding :
Offered by the NetNamedPipeBinding class, this uses named pipes as a transport for same-machine communication. It is the most secure binding since it cannot accept calls from outside the machine and it supports a variety of features similar to the TCP binding.
5. Web Service (WS) binding :
Offered by the WSHttpBinding class, this uses HTTP or HTTPS for transport, and is designed to offer a variety of features such as reliability, transactions, and security over the Internet.
6. Federated WS binding :
Offered by the WSFederationHttpBinding class, this is a specialization of the WS binding, offering support for federated security.
7. Duplex WS binding :
Offered by the WSDualHttpBinding class, this is similar to the WS binding except it also supports bidirectional communication from the service to the client.
8. MSMQ binding :
Offered by the NetMsmqBinding class, this uses MSMQ for transport and is designed to offer support for disconnected queued calls.
9. MSMQ integration binding :
Offered by the MsmqIntegrationBinding class, this converts WCF messages to and from MSMQ messages, and is designed to interoperate with legacy MSMQ clients.
What is contracts in WCF?
In WCF, all services expose contracts. The contract is a platform-neutral and standard way of describing what the service does.
WCF defines four types of contracts.
1. Service contracts : Describe which operations the client can perform on the service.
2. Data contracts : Define which data types are passed to and from the service. WCF defines implicit contracts for built-in types such as int and string, but we can easily define explicit opt-in data contracts for custom types.
3. Fault contracts : Define which errors are raised by the service, and how the service handles and propagates errors to its clients.
4. Message contracts : Allow the service to interact directly with messages. Message contracts can be typed or untyped, and are useful in interoperability cases and when there is an existing message format we have to comply with.
What is address in WCF and how many types of transport schemas are there in WCF?
Address is a way of letting client know that where a service is located. In WCF, every service is associated with a unique address. This contains the location of the service and transport schemas.
WCF supports following transport schemas
1. HTTP
2. TCP
3. Peer network
4. IPC (Inter-Process Communication over named pipes)
5. MSMQ
The sample address for above transport schema may look like
http://localhost:81
http://localhost:81/MyService
net.tcp://localhost:82/MyService
net.pipe://localhost/MyPipeService
net.msmq://localhost/private/MyMsMqService
net.msmq://localhost/MyMsMqService
What is the difference WCF and Web services?
1. Web services can only be invoked by HTTP. While Service or a WCF component can be invoked by any protocol and any transport type.
2. Second web services are not flexible. But Services are flexible. If you make a new version of the service then you need to just expose a new end point. So services are agile and which is a very practical approach looking at the current business trends.
How can we host a service on two different protocols on a single server?
Let’s first understand what this question actually means. Let’s say we have made a service and we want to host this service using HTTP as well as TCP.
You must be wondering why to ever host services on two different types of protocol. When we host a service it’s consumed by multiple types of client and it’s very much possible that they have there own protocol of communication. A good service has the capability to downgrade or upgrade its protocol according the client who is consuming him.
Let’s do a small sample in which we will host the ServiceGetCost on TCP and HTTP protocol.
Once we are done the server side coding its time to see make a client by which we can switch between the protocols and see the results. Below is the code snippet of the client side for multi-protocol hosting
What are various ways of hosting WCF?
There are three major ways of hosting a WCF services:
- Self-hosting the service in its own application domain. The service comes into existence when you create the object of Service Host class and the service closes when you call the Close of the Service Host class.
- Host in application domain or process provided by IIS Server.
- Host in application domain and process provided by WAS (Windows Activation Service) Server.
Follows the ‘software as a service’ model, where all units of functionality are defined as services.
A WCF Service is a program that exposes a collection of Endpoints. Each Endpoint is a portal (connection) for communication with either clients (applications) or other services.
Enables greater design flexibility and extensibility of distributed systems architectures.
A WCF application is represented as a collection of services with multiple entry points for communications.
What are the main components of WCF?
1.Service: The working logic or offering, implemented using any .Net Language©.
2.Host: The environment where the service is parked. E.g. exe, process, windows service
3.Endpoints: The way a service is exposed to outside world.
Explain transactions in WCF.
Transactions in WCF allow several components to concurrently participate in an operation. Transactions are a group of operations that are atomic, consistent, isolated and durable. WCF has features that allow distributed transactions. Application config file can be used for setting transaction timeouts.
What are different isolation levels provided in WCF?
The different isolation levels:
1. READ UNCOMMITTED: – An uncommitted transaction can be read. This transaction can be rolled back later.
2. READ COMMITTED :- Will not read data of a transaction that has not been committed yet
3. REPEATABLE READ: – Locks placed on all data and another transaction cannot read.
4. SERIALIZABLE:- Does not allow other transactions to insert or update data until the transaction is complete.
How do I serialize entities using WCF?
LINQ to SQL supports serialization as XML via WCF by generating WCF serialization attributes and special serialization specific logic during code-generation. You can turn on this feature in the designer by setting serialization mode to ‘Unidirectional’. Note this is not a general solution for serialization as unidirectional mode may be insufficient for many use cases.
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